Another instance running

I was using Portable Explorer++. was happy with it , even if it did crash quite often. The last time it crashed, i closed it. Then when I opened it again, it said ,'another instance of Explorer++ is already running. Please close all instances of Explorer++ before launching Explorer++ Portable.

I did all this. The same message appeared when I tried to open again. I used Process explorer and nothing running. I uninstalled and reinstalled a couple of times. Still the same. So uninstalled and installed CubicExplorer. That worked fine. It crashed a couple of times but opened again fine. The last time it crashed, I got the dreaded 'Another instance of CubicExplorer is already running. Please close all instances of CubidExplorer before launching CubidExplorer Portable.' I did all the same stuff that I tried before but still the same.
I went into the H:\PortableApps\CubicExplorerPortable and tried to run the CubicExplorerPortable.exe file from there but still the same. One thing I did notice though, in the \PortableApps\CubicExplorerPortable\App\CubicExplorer folder, there is a CubicExplorer.exe file. I double click this and it runs just fine. It has kept all my modifications and settings. I tried closing this instance and still the same. I tried running this and closing.
I dont want to reinstall it as it will loose my settings and what if it happens again? don't want to keep reinstalling everytime it crashes.
Many thanks
Mr B